Do they ask for the state to intervene? Then it is inconsistent.
If they are just unhappy with the way their hosting providers behaved, and what arguments they used to explain their eviction, then, well, it's understandable.
If they are asking the state to enforce any contracts/agreements then that is very much consistent with a laissez-faire stance.
The 'Freedom of Speech'-line of reasoning is invalid in a laissez-faire context, though it _is_ however an argument I'd expect to bee seen as valid by several large crowds between the political extremes.
I agree about the freedom of contract, and assume that the terms of service likely included the right of the provider to cancel the service and terminate the contract at any time, without giving any reasons.
The problem I see that everyone sees e.g. Parler as so toxic that they expect their reputation to increase, on average, for kicking them away. It's the low tolerance to dissent and the high social opinion pressure what is troubling, not the action.
If they are just unhappy with the way their hosting providers behaved, and what arguments they used to explain their eviction, then, well, it's understandable.